Loans and Leases and the Allowance for Loan and Lease Losses (Troubled Debt Restructuring & Narrative) (Details 6) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2018 USD ($) contract	Mar. 31, 2017 USD ($) contract	Dec. 31, 2017 USD ($)
Information related to loans modified as a TDR
Recorded Investment	$ 60,200		$ 60,100
Available Commitments to Lend Additional Funds on Loans Modified as TDR	$ 1,300		$ 1,500
Number of Contracts \| contract	180	210
Recorded Investment (as of period end)	$ 3,341	$ 7,306
Increase in Allowance (as of period end)	$ 61	$ 71
Residential Mortgage \| Maximum
Information related to loans modified as a TDR
Period of Time Loan Being Fully Amortized	40 years
Land Loan \| Maximum
Information related to loans modified as a TDR
Period of Time Loan Being Fully Amortized	360 months
Extending Balloon Payments	5 years
Commercial
Information related to loans modified as a TDR
Number of Contracts \| contract	1	6
Recorded Investment (as of period end)	$ 503	$ 4,262
Increase in Allowance (as of period end)	$ 0	$ 1
Commercial \| Commercial and Industrial
Information related to loans modified as a TDR
Number of Contracts \| contract	1	5
Recorded Investment (as of period end)	$ 503	$ 3,858
Increase in Allowance (as of period end)	$ 0	$ 1
Commercial \| Commercial Mortgage
Information related to loans modified as a TDR
Number of Contracts \| contract	0	1
Recorded Investment (as of period end)	$ 0	$ 404
Increase in Allowance (as of period end)	$ 0	$ 0
Consumer
Information related to loans modified as a TDR
Number of Contracts \| contract	179	204
Recorded Investment (as of period end)	$ 2,838	$ 3,044
Increase in Allowance (as of period end)	$ 61	$ 70
Consumer \| Residential Mortgage
Information related to loans modified as a TDR
Number of Contracts \| contract	1	1
Recorded Investment (as of period end)	$ 112	$ 98
Increase in Allowance (as of period end)	$ 0	$ 0
Consumer \| Automobile
Information related to loans modified as a TDR
Number of Contracts \| contract	98	113
Recorded Investment (as of period end)	$ 2,179	$ 2,303
Increase in Allowance (as of period end)	$ 47	$ 52
Consumer \| Other
Information related to loans modified as a TDR
Number of Contracts \| contract	80	90
Recorded Investment (as of period end)	$ 547	$ 643
Increase in Allowance (as of period end)	$ 14	$ 18

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554

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-Publisher FASB
-Name Accounting Standards Codification
-Glossary Recorded Investment
-URI http://asc.fasb.org/extlink&oid=65880944

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